1. Field of the Invention
The present invention relates to a substrate for a liquid discharge head forming a liquid droplet by discharging a liquid such as an ink or the like, a liquid discharge head using the substrate for the liquid discharge head and a method of manufacturing the same.
2. Description of the Related Art
In conventional, a memory element substrate corresponding to a main portion of an ink jet head is structured, as shown in FIG. 18, such that an electric wiring, a member 523 constructing a liquid chamber filled with an ink, and the like are formed as a memory element substrate 501 on a substrate 502 in accordance with a film forming technique. As the substrate 502, for example, a Si substrate having a thickness of 0.5 to 1 mm is employed. A plurality of ink supply ports 503 constituted by long groove-shaped through ports are opened on the substrate 502 for receiving the liquid within the liquid chamber from the external portion. Electrothermal converting elements 504 are arranged at both side positions of the respective ink supply ports 503 on the substrate 502 in a zigzag manner every one line.
The liquid chamber is communicated with each of the ink supply ports 503, and is formed such as to internally pack the electrothermal converting elements 504 formed in both sides of each of the ink supply ports 503. An ink flow path wall 507 forming an ink flow path communicating with a position on each of the electrothermal converting elements 504 from the ink supply port 503 is formed within the liquid chamber, and a discharge port 508 is open to an upper side of each of the electrothermal converting elements 504. Further, an electric wiring (not shown) made of Al or the like and provided for supplying an electric power to each of the electrothermal converting elements 504 is formed on the substrate 502. The electric wiring is connected to an electrode portion 505 connected to an external electric power supply source. The electrode portion 505 is provided near both ends in a longitudinal direction on the substrate 502, and has a plurality of connection members 506 formed side by side, made of Au or the like and called as a bump.
Further, in accordance with a multicolor and a high quality picture of a recorded image as typified by a photo grade in recent years, it is intended to increase a number of nozzles (ink discharge ports) and make a nozzle density narrow in pitch, in the ink jet head. Accordingly, an increase in numbers and a narrower pitch are intended with respect to the electrothermal converting element formed on the memory element substrate. In addition, since a function of the electrothermal converting element is made high, an increase in numbers and a narrower pitch are intended with respect to the bump 506 provided on the electrode pad of the electrode portion 505.
Accordingly, there has been considered that the electric wiring for introducing the electric power supplied from the head outer portion to the electrothermal converting element is made thick in film on the substrate in view of necessity of intending to make a resistance low.
However, in the prior art mentioned above, in the case that forming the connection member 506 such as the bump or the like is executed on an upper layer of a head chip corresponding to the memory element substrate 501 in accordance with an independent step after forming the electric wiring which has been considered to be made thick at this time, a number of manufacturing steps of the ink jet head is increased in addition that a lot of time is required for forming the thickened electric wiring itself. Accordingly, there is a problem that a cost is increased.